Suspected Muslim rebels wearing police and military uniforms detonated bombs and opened fire on Tuesday in a southern Philippine town, triggering clashes that killed at least nine people, officials said.

Suspected Muslim rebels wearing police and military uniforms detonated bombs and opened fire on Tuesday in a southern Philippine town, triggering clashes that killed at least nine people, officials said.

The attack began with a series of simultaneous bomb blasts that hit a sports center, near a Roman Catholic cathedral and the residence of a local judge on Basilan Island, a militant stronghold where rebels and troops have repeatedly clashed, said marine commandant Maj Gen Juancho Sabban.

He said at least three marines were killed and one was wounded while trying to secure the provincial capital of Isabela city. Four civilians and two police officers also were among the dead, said Basilan police chief Tony Mendoza.

A regional military commander, Lt Gen Benjamin Dolorfino, said the attackers were disguised in police and military uniforms. They set a vehicle on fire and fired at anyone "who looked like military or police" as they fled the scene, Mendoza said.

Security forces were in control of Isabela and the city was cordoned off, Sabban said.

"We are advising the civilians to stay calm and not to panic and let the security forces cordon the area," Sabban said.

Muslim rebels have been fighting for a separate homeland in the predominantly Catholic nation for decades. Predominantly Muslim Basilan province, about 880 kilometers south of Manila, is home to the Al-Qaeda-linked Abu Sayyaf group, notorious for kidnappings and bomb attacks over the last two decades, and the separatist Moro Islamic Liberation Front, which has a cease-fire with the government while negotiating for autonomy.

Sabban said it was not clear who was responsible, but the Abu Sayyaf and the Moro rebels cooperated in past attacks on civilians and security forces on Basilan.